Sound transmitting and receiving apparatus



A. M. KENNEDY SOUND TRANSMITTING AND RECEIVING APPARATUS Filed March e, 1926 ATTORNEY Patented Oct. 16,1928.v

- FUNQITED STATES AUBREY Megan-nann orimw Yonx, N. Y.

SOUND TRANSMITTING AND RECEIVING APPARATUS.

Application filed March 6, 1926. Serial No. 92,684.

The object of the present invention is to provide a sound transmitting'and receiving device suitable for use in conjunction with the transmitters or' receivers of telephones,

ear phones, or loud speakers of radio apparatus, etc., which shall result in increased volume as compared with the usual iron diaphragm, and which will also result in more natural transmission, or reproduction of sound waves. 3 The invention will be understood by reference to the accompanying drawings, in which-- Figure ,1 is a sectional elevation of a radio 7 loud speaker embodying improvements and Figurefl is a horizontal section onthe llne 2-2, Figure 1 Referring to the drawings, A represents a casing having-an internal chamber for the reception of the magnet 1, having the pole pieces 2 which lieslightly below the top of the casing. The casing is threadedto receive a cap 8 which closes the casing except for a central outlet 3 surrounding which is aneck i to receive a horn 5 or other transmitting device for the sound waves. The pole pieces 2 of the magnet lie immediately below and act upon the diaphragm directly, and the diaphragm may be the usual disk 0i iron, or other materiahas customary. Stretched tightly over the upper surface of the diaphragm 6 and in contact therewith is a piece of elastic material, preferably thin leather, such as pigskin. In the present embodiment of the invention, the marginof the side pieces of elastic material are brought over the edges of the metallic diskandturned e inward so that they may rest upon the shoulder formed by the top wall of thecasing A. The cap 3 is provided with an annular shou lcler 7, which overlies the top of the casing. Hence when the cap is screwed downward,

with the diaphragm and itselastic covering in place, the covering is firmly secured in position.

As stated above, the pig skin, or other ela's-- tic covering .for the metallic disk should stretched upon the disk. This can be'done in any suitable manner as by wettingv the leather, or othermaterial, prior to stretching it upon the metallic disk and then securing themargins of theleather covering, as illustrated in Figure 1, prior to thedrying of the covering. The drying operation will cause the covering to contract and the margins being held, the contraction will cause a stretching and' tensioning of the material, as Will be understood by further explanation. If desired, the inturned margins of the covering may be secured by glue, or otherwise, 60. to the disk. In ,the use of the ordinary metallic diaphragm, there isa constant condition under which only part of the tones to be reproduced are acted upon naturally and without more or less distortion'through the mechanical action of the disk and the nature of the material with which it isconstructed.

Such tones are given an unnatural stridency. .By means of the present invention a simple and effective device is provided for enabling reproduction of the sound waves, as

in the transmission or amplificatio thereof,

by two contacting members which ave relatively different vibratory reactions and in which ,all of the sound waves passing from 35 the metallic diaphragm are received and modified by the non-metallic member.

It'willbe understood that I have illus trated only oneof the many possibleforms of the invention, the drawings being merely illustrative of the principle of my invention,

what I claim and desire to secure by Letters Patent, being as follows:

1. In ,rsoun transmitting-rand receiving apparatus, a' casing having a sound discharge aperture, a metallic diaphragm with-- 'in the casing and a thin leather material under tension and held in said casing adjacent the metal-lic'diaphragm and oo-extensive with its exposed area so as to completely shield the discharge outlet fromthe direct vibrations of the diaphragm.

2. In sound transmitting and receiving apparatus, a metallic diaphragm, and a thin tensioned elastic member directl applied to one faceof the diaphragm and com letely covering the effective area or said diap raginincluding its axialportion. Y

3. In sound transmitting andreceiving I apparatus, a casing having a, sound discharge aperture, a primary diaphragm within the vibrations of the primary diaphragm, said casing and adapted for magnetic. vibration, secondary diaphragm being adapted to genand a secondary tightly stretched diaphragm erate sound Waves by its vibration and trans- 10 intermediate the primary diaphragm and mit them through saidoutlet. 5 the sound discharge aperture and co-exten- In testimony whereof, I have signed my sive with its exposed area, so as to completely name to this specification.

shield the discharge outlet from the direct AUBREY M. KENNEDY. 

